To demonstrate improved recovery from LBNP with GIH, we need to extend recovery time to 30 minutes. A Stand Test has been added to our protocol with the objective of perhaps replacing the LBNP with the Stand Test. If the Stand Test gives the same information as the LBNP, we will be able to conduct many more experiments in the future. An orthostatic tolerance index (Tx) is being developed to better define autoregulation of cerebral blood flow.